Powder paints for use as coating materials are well known in the art and comprise resins, pigments and additives. Powder paints are applied onto metal supports by being spread in the air, caused to electrostatically adhere to the surface of metal supports, and then heated to polymerization temperature so as to obtain permanent adhesion to the metal support.
Generally speaking, powder paints have a low impact on the environment, while ensuring good protection to the surface of a support body to which they are applied. Other conventional methods of application are adopted for coating non metal plane surfaces, e. g. deposition by making use of a dispenser device. Application times of powder paints are quite short and the range of obtainable colors is wide.
More important, owing to the fact that powder paints do not include any specific solvent evaporating when undergoing polymerization, their use has shown very low risk of causing human diseases.
Due to all such advantages the powder paint technique for finishing metallic and non metallic articles has been adopted since many years in place of solvent paint technique.
Moreover substantial efforts have been made to develop powder paint techniques for image formation on various kinds of support.
U.S. Pat. No. 4,395,263 discloses a process to produce a laminate with permanent decorations by a sublimatic transfer printing process according to which an image is sublimatically transferred by heating.
Such a process provides for the following stages:                arranging a rolled metal support comprising at least one binding material surface stratum including a predetermined pigment;        coating the binding material stratum with a transparent layer of thermosettable material receptive to a sublimatic dyestuff;        heat curing or drying the rolled metal support;        arranging an auxiliary carrier web, such as a paper sheet, on which a “negative” image is formed by sublimatic dyestuff;        transferring, e. g. by contact and heat-induced sublimation, the sublimatic dyestuff from the auxiliary carrier web to the transparent layer.        
In this way, a “positive” image on the metal support is not directly formed but is transferred from an auxiliary carrier to a transparent layer, thus the image is impressed or fixed by transfer on the outer surface of the transparent layer.
U.S. Pat. No. 4,354,851 discloses a method for making a decorated water-resistant rigid panel. In such a method use is made of a dried or cured rigid panel and a printed sheet, the printed sheet bearing a decoration formed by a sublimatic coloring agent. One surface of the rigid panel is coated with a transparent polymeric cover and may have an additional substrate coating or layer of polymeric or other materials. The printed sheet is put and kept into contact with the rigid panel coated surface, and pressure or heat is then applied to the printed sheet, whereby causing transfer of sublimatic coloring agent from the printed sheet to the transparent polymeric cover.
U.S. Pat. No. 4,657,557 discloses a sheet for sublimatic transfer by heat application of a sublimatic color-based decoration. The decoration preparation includes the following stages:                coating one surface of a transfer sheet or film surface with sublimatic inks, and its other surface with a heat-resistant resin;        drying of inks and resin;        coating an image-receiving support with a polymerizing resin;        putting the transferring sheet or film into contact with the image-receiving support;        heating in order to cause the decoration to be transferred from the transfer sheet to the image-receiving support.        
WO-2004/035311 patent application discloses a process for decorating a substrate by transferring onto it at least one sublimatic ink.
Such a process includes the stages of:                coating a substrate surface with a polymeric transparent or translucent polymer;        putting a transfer sheet into contact with the coated substrate surface; and        transferring an image or decoration from the transfer sheet to the coated surface.        
U.S. Pat. No. 6,686,315 discloses a method of coating a building material surface comprising:                arranging a building material having a surface coated with a sublimatic ink-based image receiving substrate;        printing a transfer image on a transfer means (paper sheet); and        transferring the image from the transfer means to the substrate.        
The above-mentioned patents disclose and teach processes for forming an image on a support involving the use of an auxiliary carrier, such as a paper sheet, on which an image or a decoration is formed, in most cases a “negative” of the image or decoration to be fixed on a support, the image being obtained by a sublimatic ink. The auxiliary carrier is brought into contact with the support, preferably at a support portion provided with a layer of material receptive to the sublimatic ink, whereby causing transfer of sublimatic ink “positive” image from the auxiliary carrier to the support. Image transfer is made easier by applying heat at a predetermined temperature to the carrier while being in contact with the support.
The image or decoration obtained by such a technique has a high image definition but involves substantial waste of sublimatic ink, that only partly sublimates during the image formation process.
Moreover, the auxiliary carrier, often cannot be re-used after image transfer, and thus has to be discarded.